Chain-adjusting device



Dec. 9, 1930. 4r-'. c. THOMPSON CHAIN ADJUSTING DEVICE Filed Feb. 2 Sheets-Sheet l y.

:NVE TOR f-MQ v ATTORNEYS slot 34.

is guided atthe sides bythe walls of 'the Referring now particularly to Fig, 2, it will be seen that the recess 3,1 is longer than the ratchet bar and that with the device in the position shown in this figure, the end i Y wall 35 of the recess engages the ratchet bar,

While the other'end wall 36 of the recesscis spaced away from the bar. In effect the end walls 35 and 36 of the recess constitute spaced l abutments, the' spacing of whichlis greater It will thanthe length of .the ratchet bar. thus be seen that while the ratchet bar moves with the plunger ll when the ,abutment 35 engages the bar, there neverthelessis a limited amount of relative movement between the plunger *and bar, the amount offwhich 1s determined by the Aspacing ofthe abutments.

The arrangement may be said to` beone providing 'a lost motion connection between the adjusting plunger andthe stop device. The Y l operation of the device and thepurpose of and advantages Vto be derived from'the novel r .arrangement of stop'-mechan1snr which I 25 ing..

have provided will be clear from the follow- As slack in the chain develops the yplunger 11 is moved in adirection to Vpress the Vsprocket 14 against' the chain'to'take up thel slack, and in thismovement of the plunger the abutment 35 engages the ratchet bar 25 and the bar mpves along with the plunger.

Uponmovement of the bar the serration's 26 trip over or ratchetzpast the teeth 29on" the head of the "spring pressed pin 27. The lamount of such movement is determined byk Y the'looseness-of the chain. VVhen the chain is tight, `the movement ceasesand the stop i devicevis setin a position' to preventmove-f ment of the adjusting plunger toa positionV win which the chain would enough tov permit of sufficient backwardl movement of the adjuster as "would caused movement of the adjusterbefore the device n B acts to stop the movement,whichisveryloose; .y 1 4 l yIt is pointed out,-however, that 'the adjuster may move backward inthe'amount ofy the clearance at 37 between-,the'endof the ratchet bar and the abutment-136W The.

amount of clearance, however," is-,notA great objectionable slack vor looseness in the chain. In other words, the clearance is so. pro`portioned as to permit only ofa predetermined limited amount of backward movement;

VVThe arrangement, therefore, is one Which- Vwillallow a limited amountfo'fbackward advantageous, for the 'reason tha't y. should Vforces develop, other'than those of the fad-1 fect of tightening theV chain, 'the :,tdjuster'is'4 i' enabled Vto move' backward any 'amount to compensate therefor, and -vthus the chain lwill V notY become too "tight :as would-be the/case.' Vif the-follow up. stop device. B acted to lock Vjuster device itself, whichV would have; the, ef-V run objection'ably' to stop s'uch'rnovement.

the Vadjuster in its adjusted position without the provision ofmeans for compensat- 1ng orsuch forces. j j

f By-way of example, letus assume that the adjuster device has ,taken the slack out of the chain yand that a change of temperature `takes -placewhich vwould have vthe elfect of 'tighteningthe chain still more. Under such conditions, without provisionv to the con- "trary, the A'chain would becomerobjectionably tight'andseriousstrains would develop in the drive. .:Through the provision of compensating means such as has'been fully described hereinbefore-,I overcome the above objections, and as a result, a very effective chain'. `drive is provided which will have longflife'f f y 1. A tension adjusterwfor endless chains including yieldable means 'normally -operatinor iongthechain-'in a directionv to take up slack `therein,means, for preventing movement of the adjuster to positions ofloose adjustment,

Va lostg=motion connectioni'betwee'n the first means and thel second means adapted to set the second'mefans when thefir'st means moves operating on the mounting-to movelitwithV its sprocket -in-'a directionto: operate on the chain to Atake" up slack thereinas A it develops; ad-

justable Y'stop-means for preventing move-- HVmentoffthe" sprocket wheelV and its mounting to positions in `which objectionable slack in the chainrwou'ld develop, said stopmeans in'- cludinga'memberhaving ratchet teeth, anda stop member engaging the ratchetteeth, one Y Y f of said members.; being movable with. ther mounting andthe 'other being .carried by a liked part; anda lost motion connectionbetween the mounting yand :its v'member of' the stop' means `'whereby 4a limited vamount of movementofthemounting in a direction inging;

which Vslack in the chain would tend to develop ispermitted before the stopmeans acts "3.fIna .tension adjusterforendless.chains,

, the combination; of a. sprocket wheel, agmovfx ablefmounting for Vthe sprocket fwheel, spring meansy for VVmoving the mounting and wheel against fthe; chain to take up slackl therein, ratchet means actuated byithe mounting for- Y; preventing return of the adjuster .to-v posi: :tions of loose adjustment, and a'lost motion 4'connection betweenfth'e mounting' and the ratchetmeans wherebyf'a limited amount of i `backward lmovement ofthe-mountingmay oc-k lr cur,-the amount of suchxmovement being me 

